Making condensation products of



Reiaued Feb. 12, 1935 MAKING CONDENSATION PRODUCTS OF UREA AND ALDEHYDEKurt Ripper, Berlin, Germany, assignor, by meme assignments, to'AmericanCyanamid Company, a corporation of Maine No Drawing. Original No.1,762,456, dated June 10, 1930, Serial No. 740,406, September 27, 1924.Application for reissue June 9, 1932, Serial No. 616,358. In AustriaAugust 25, 1924 19 Claims.

This invention relates to themanufacture of condensation products fromurea, derivatives of urea or materials which during the treatmentproduce urea or derivatives thereof on the one hand and aldehydes,particularly formaldehyde, on the other. According to known methods formanufacturing such condensation products liquid initial condensationproducts are prepared, which represent the hydrosol of the emulsioncolloid formed by the two starting materials. If these sols aretransformed into gels forming either thin layers, such aslacquer-coatings, or more compact bodies, such as products turned (as ina lathe), or imitationsof glass, there is always a remainder of theaqueous solvent retained by the mass, which remainder shows a markedvapor tension. By this tension the practical utilization of thecondensation products is limited to a certain extent. If the tension ofthe water vapors in the mediumsurrounding the mass is less than that inthe latter,

water vapors will escape from the gel after some time. On the otherhand, if the pressure of the water vapors of the surrounding mediumis-above the pressure within the material, water vapors will be adsorbedby the latter from the surrounding medium. Both these proceedings aredisa'dgvantageous, even detrimental'to the mass and in the case of thehardened mass being stored up for a long time may cause fissures orcracks in the material. Another drawback due to the use of water asdispersing agent is, that influencing the physical, especially theelastic properties of the mass, is almost impossible, as nearly none ofthe substances appropriate for such influencing can be dissolved toproduce clear solutions. Finally also the disadvantageous property ofthese hydrogels may be mentioned, that they lose their glasslike aspectat higher temperatures.

Now I have found that all these disadvantages can be prevented. ifprovision is made for small quantities of such organic media beingpresent within the gels, which are capable of forming transparentsolutions or mixtures withthe condensation product of urea' andformaldehyde.

specially favorable results can be obtainedflf the water is entirely orpartly removedand substituted bysaid organic media, an organo-sol of thecondensation product being thus formed either entirely or partly, whichorgano-solby hardening is transformed into an organo-gel.

For removing the water, having served as dispersion medium, from thesol, and for replacing it by an organic medium prior to the sol beingtransformed into the gel, different ways may be chosen.

So for instance he greatest part of the water may be expelledmechanically by hydrophobe conduct of the polymerization process, orelse the mass may be hydrophile, in which case the greatest part of thewater is removed in a' vacuum. This may be done in accordance with theprocess described in Ser. No. 700,736 filed March 20, 1924, Patent No.1,687,312 of October 9, 1928. The cited application deals with a processin accordance with which a neutral or alkaline mixture of urea andformaldehyde is caused to be boiled for a short time and then thereaction product produced is further treated in'an acid medium. By means01' the addition of an acid reacting condensation means it happens in adetermined period of time that the emulsion colloid arising is ahydrophobe,

that is to say, the water separates for the greater part on cooling andthe remaining water amounts to no more than that which can be absorbed.

Thereafter the hydrophobe or hydrophile colloid, which still contains asmall fraction of the original quantity of the employed water, istreated with non-aqueous, organic media (solvent A) in order to removethe remainder of the water as far as possible. The best result isobtained, if such organic agents are used, which are capable of formingwith water vapors binary, ternary or quaternary mixtures of vapors(Confere. g. Beilstein-Prager-Jacobson, Vol. I, (4th edition, 1918) page295). By treatment with these agents, preferably elfected in vacuo, thegreatest part of the water still present can be removed. The sols mustcontain so much of liquid constituents that their state of consistencyallows pouring into molds. This state may be obtained by the first addedorganic media, or, if not, by adding further agents (solvents B),capable of expelling and replacing the water entirely or partly, whenthe mass has already attained the state of a gel.

After setting (congealing, solidifying) the gel must contain organicmedia (hereinafter called solvent C), which may either be added to themixture of the starting materials or at anyconvenient stage of theprocess, that is to say either to the sol or to the gel.

If it is intended to obtain clear products, such organic solvents are tobe chosen, which are capable of forming with the generated gel clearsolutions, either by dissolving it or else by being dissolved themselvesby the gel. For obtaining the desired efiect the amount of the organicagent must not necessarily be such as to suflice for alone building upthe structure of the gel. 011 the contrary it is sufficient, if thewater present in the condensation products of urea and formaldehyde ispar ly replaced by an organic medium or if said partakes in orcontributes to forming the structure ofthe gel. If the organic agent(solvent C) destined to form part of the gel, is by itself capable ofbeing partially removed during evaporation of the water, by generationof volatile vapor mixtures, the addition of the solvent A may bedispensed with. In like manner also the addition of the solvent B mayunder like circumstances be omitted.

Organic solvents of the most various kinds may be used as solvent A,such as for instance hydrocarbons, alcohol, ether, aldehyde, ketones andthe like, or mixtures thereof which maybe either of the aliphatic,aromatic or hydro-aromatic series,

' which possess the faculty of forming with water vapors volatile vapormixtures, in order to remove the water'entirely or partly from the masssmall quantities of solvents as is possible.

' does not show any more'the disadvantage of losas long as the latter isin the stage of a sol, and to replace it.

For use as solvents B such organic solvents are appropriate whichpossess the property of removing entirely or partly the water from themass, when in the state of the gel, and of replacing it therein.

As solvent C such media are adapted, for which the congealed emulsoidpossesses a special dissolving capacity, it being not necessary, thatthesemedia be liquid. Of course such substances have mostly a pronouncedcapacity for dissolving themselves the emulsoidand in many cases itcannot be distinguished with full certainty, which of the constituentsof such mixture is to be regarded as the sol-vent and which as thedissolved one. Consequently the substances adapted for this purpose maybe of most various composition. 50 for instance glacial acetic acidhas'aboutthe'same effect as benzylalcohol, and glycerine an effectsimilar to that of concentrated formic acid or sugar. It is to beseerLtherefrom, that the essential item in this connection is not thechemical composition of the substance destined to remain within thefinal product, but its property of being either clearly dissolved bygels or else of dissolving them so as to form a clear solution.

According to the different uses the final product may be intended for,the amount and the kind of the solvents will vary. For producing e. g.lacquers preferably such organic solvents are used, the boiling point ofwhich is as low as possible, and by repeated addition and distillationthe substantially total amount of water is removed from the emulsoid. Ifsolid masses are to be made, care is to be taken to operate with as Forthis purpose it may bejpossible to dispense with the use of solvent Aand to add only the solvents,

B and C to the emulsoid concentrated by evaporation as far as possible,and thereafter hardening the mass. Thereby the thickening of theemulsoid by evaporation is advantageously eifected in vacuo in order toavoid premature influence of too high temperatures. In this manner gelscan be produced, the water vapor pressure of which is substantiallynaught and whose other properties areby the described method altered tosuch degree, that the greatest variation of the vapor tension of thesurrounding atmosphere has no influence on'the mass. Furthermore thelatter ing its glasslike aspect and transparency at higher temperatures.I

In practice the hereinbefore described method can be. utilized forvarious and manifold pur+ 'siderable electric insulating power.

organic medium, even in the presence of water,

poses. It is not limited to the manufacture of pure condensationproducts of urea and aldehydes only. On the contrary mixtures of saidcondensation products thus prepared, with other plastic substances oragents provoking plasticity and with organic media of all kind may bemade, provided that these additions are capable of forming clearsolutions with the emulsoids or with the mixtures of emulsoids underconsideration:

So I have found that particularly all celluloses, derivatives ofcellulose and products of decomposition' or transformation of celluloseform transparent, uniform (homogeneous) mixtures with the emulsoid. Byvariation of the proportions of the constituents of such mixtures anydesired degree of elasticity can be obtained. Lacquers may for instancethus be produced, which have the suppleness of cellulose-ester lacquersand at the same time allow polishing to the highest degree. Suchlacquers are in no Way affected by moisture or water and show con- Theymay be employed without any filling materials in a state as clearas'water or glass and will give highly brilliant, water-proof insulatingcoatings, which very well resist atmospheric influences. But on theother hand they may also be mixed with any inorganic or organic, solubleor body colors, with filling materials of all kinds, etc.

The organosols consisting of a mixture of ureaaldehyde emulsoids andcellulose-derivatives can beutilized for manufacturing artificial silk.For this purpose the solution is caused to enter from very fine nozzlesinto a precipitating (setting) bath, preferably water or some aqueoussolution of an electrolyte. By spinning the fine threads thus produced ayarn is obtained which is much less affectedby water than any kind ofartificial silk known hitherto, and which can easily be dyed.Furthermore the advantage is offered that by variation of theproportions of the mixture any desired degree of hardness and strengthcan be obtained. Silks may be made containing only a few per centofcondensation products from urea and formaldehyde up .to such containing"aggravating (roughening of the surface) takes place, not knownheretofore. According to the composition of the organosol employedtherefor,

the yarn or artificial silk will become either harder or softer, but inany case considerably less sensitive to water and detergents (soap,etc.)

Furthermore said mixtures can advantageously be employed formanufacturing non-inflamma-' ble films and photographic plates. Also inthis case variation of the proportions of the ingredients enables ofmaking productsanswering all special requirements. For producingkinematic films, requiring the highest possible degree ofelasticity,relatively large proportions of cellulose derivatives are to beemployed, whilee. g. for

this purpose a liquid is chosen as addition, which is soluble in themass andhas a very high bolling point.' By variation of the amount ofthis liquid said adjustment can be effected.

It is also possible to introduce (say in solution, if desired) camphor,bomeol or the like into the condensation products of urea and aldehydesand to obtain also clear mixtures. If only small quantities of camphoror borneol are added the gels thus composed possess, when hardened ingeneral nearly the same properties as the crystal-like products free ofcamphor or borneol but they are more supple or softer and therefore canbe easier worked by mechanical means than those made with liquid organicsolvents only.

Products of quite different properties are obtained by employing largerquantities of camphor or borneol, especially when mixed with hydrophobematerials. In such case the masses become highly plastic and doughlike.Plates, sticks, rods, tubes and any other sort of compact or hollowbodies may be made therefrom, which in contradistinction to masses madewith smaller quantities of dispersing agents show the peculiar propertyof softening in the warmth, thus en abling of easier working. While theheretofore known condensation products of urea and formaldehyde did notallow stamping, these mixed masses can be stamped even when fullyhardened in order to manufacture various articles therefrom, such asbuttons, combs and the like.

The hardening of the masses composed according to the presentdisclosures may be effected ,as usual by employing heat or else inthe"cold that is to say at ordinary temperature. In general all theconditions and indications mentioned above will also apply, whenhardening in the cold is intended, but'in the latter case, owing to theomission of the influence of higher temperatures, some small quantitiesof water may remain within the mass. Consequently such products may notfully show all the perfect qualities of masses hardened by the heatingmethodf Nevertheless there may be cases where operat ing at ordinarytemperature is preferred, either for the reason, that employing heat isnot possible or that very rapid hardening is desired. So for instancethis method may be chosen for producing glass-clear castings (e. g. forsculpture), which hitherto .could not be made by known means. a

As is seen, the products obtained by the present method are of variousforms and properties, but they all are characterized by the feature,that their water-vapor tension is eliminated or reduced to a minimum bythe presence of an organic medium, or at least its effect is obviated.

The products therefore represent in the hardened state perfectlyunalterable, stable, transparent gels. .Their physical and particularlyelastic properties can be influenced within very wide limits. Thehardened products possess great electric insulating power and becomeelectrically charged themselves on rubbing.

' Examples 150 parts' by weight of a hydrophobe intermediatecondensation product of urea and formaldehyde are dissolved in 50 partsby weight of ethyl alcohol and. 15 parts by weight of amylasetate(solvent B) are added to the solution. The solution thus obtained isthickened by distillation, then 15 parts by weight of benzyl-alcohol areadded and distillation is continued for short lacetate; The mixture isthen 150 parts by weight of a hydrophobe intermediate condensationproduct from urea and formaldehyde are dissolved in 50 parts by weight01' alcohol and 5 to 10 parts by weight of benzene, (in the trade calledbenzol) are added to the solution. This mixture isdistilled in avacuum,a ternary mixture of water, benzene and alcohol being thus caused toescape. After about half of the entire mass has been distilled ofi,alcohol and benzol are again added and distilling oil is continued. Inthis manner it' is possible to remove nearly the whole amount of waterwithin short time. To the alcoholsol of the condensation product again50 parts by weightof alcohol are added, in which two parts by weight ofborneol'have been dissolved, and distillation is continned until theconsistency of syrup is attained. When this mass at temperatures up to100 C. is hardened until its weight remains constant, it will alsorepresent a transparent, perfectly stable organo-gel.

condensed in vacuo to the consistency of syrup and thereafter mixed with15' parts by weight of benzyl-alcohol and 2 parts by weight ofamylpoured into molds and hardened. The remainder of the water, held bythe jelly, can be driven off at a raised temperature. The gels thusobtained are transparent, clear as glass and stable.

100 parts by weight of a hydrophile condensation product of urea andformaldehyde are conparts by weight of amyl-acetate, parts by weight ofethyl acetate and 10 parts by weight of toluol as an organic diluent areadded. The resulting product is a lacquer solution, which in anyconvenient manner can be applied to all sorts of objects. After drying,whereby the remaining water will be driven ofi, the coating will behighly brilliant, very elastic, transparent, capable of being polished,and will become electric when rubbed.

A solution made in similar mannerwith modifled proportions can beexpelled from very fine nczzles into. an aqueous solution serving asprecipitating (solidifying) bath and the threads thus obtained can bespun to artificial silk, which proves'to be superior to any known kindof artificial silk as far as insensibility to water, exuberance andfitness for being dyed are concerned. But the solution may also bedistilled in a vacuum and then hardened to form molded, transparentobjects; V

To 150 parts by weight of a hydrophile sol from urea and formaldehyde150 parts by weight of methyl-alcohol are added. Thereby initially whiteflocks will be precipitated, which however, dissolve afterwards in theexcess. To this solution 50 parts by weight of a 10% solution ofacetyl-cellulose in benzylalcohol are added. This mixed organosol can beutilized for all the pur-- poses indicated in Example III, that is aslacquer or for manufacturing articles of any form, such as films,plates, material for being turned, etc. The water still contained in theorgano-sol escapes as in Example IV.

250 parts by weight of a hydrophile condensation product of urea andformaldehyde are concentrated in vacuo and thereby reduced to about 160parts by weight. To the resultingmass, having the consistency of syrup,50 parts by weight of ethyl-alcohol and 5 parts by weight of henzene(benzol) are added. The mixture will at the beginning be cloudy butafter short time will become clear, whereafter the clear solution issubjected to distillation in vacuo. After the bulk of the liquid hasbeen expelled, another.50 parts by weight of ethyl-alcohol are added andalso.

distilled off in the vacuum. After the greatest part of the liquid isexpelled, another 50 parts by weight of ethyl-alcohol are added and alsodistilled off in the vacuum. After the greatest part of the liquid isexpelled a solution of 2 parts by weight of camphor in 5 parts by weightof benzyl-alcohol is added-and the mass is for a. short timeconcentrated in the vacuum. Thereafter the clear mixture is poured intomolds and hardened at temperatures up to C.

The gels thus obtained are transparent, per- 1 fe'ctly stable and havethe aspect of mountain (pebble) crystal.

' VII To parts by weight of a hydrophobe condensation product from ureaand formaldehyde 10 parts by weight of benzyl-alcohol are added and 20parts by weight of camphor dissolved in as little alcohol as ispossible. The mixture is then well kneaded. The resulting mass isdoughlike and loses the remaining water on hardening. The hardened gelmay be used for making transparent objects of any kind or form, "whichwill have a high degree of elasticity.

VIII

To 100 parts by weightof a hydrophile condensation product of urea andformaldehyde 20 parts by weight of glycerine are added, then the mass isconcentrated. Thereafter 5 parts by weight of an agent accelerating thehardening are added, such as for instance ammoniumphosphate. The mixturewill set after a short the mass is poured into molds and time to a hard,transparent, glass-clear gel, which without any further hardening can betaken out, from the molds and be worked by any mechanical means.

150 parts by weight of a hydrophile condensation product of urea andformaldehyde are evaporated to the consistency of syrup, then 2 parts byweight of acetanilide, dissolved in water, are added and distillation iscontinued. Thereafter hardened.

Transparent, glass-clear masses are obtained 'ture is distilled to thethereby, the elasticity of which is considerably higher than that ofsimilar masses hitherto made.

To 150 parts by weight of a hydrophobe conthereby are also transparent,clear as glass and stable.

To 100 parts by weight of a hydrophobe'condensation product of urea andformaldehyde 50 parts by weight of ethyl alcohol are added and by weightof naphthalene dissolved in 8 parts by weight of benzylalcohol is addedand the mixconsistency of syrup. Then the mass is poured into molds andhardened. Also by these, steps transparent, glass-like, perfectly stablemasses are obtained. v I wish it to be understood that I do not desireto be limited to the exact details and proportions as described, forobviousmodifications will occur to any person skilled in the art.

In the following claims I use the term urea to include not only urea andits derivatives, but,

also any prime material yielding urea or derivatives thereof.

In this specification, by hydrophile emulsion colloids such emulsoidsare understood, which are .capable of being mixed with water to formuniform, homogeneous colloidal solutions, whilst hydrophobe emul soidsdo not mix'with water or do so only to an exceedingly low extent, andtherefore during their generation from watery solutions are themselvesmechanically separated. The meaning of these expressions and the way ofproducing either hydrophile or hydrophobe emulsion colloids is explainedin the U. S. A. patent application Serial No. 700,736 filed March 20,1924, Patent No. 1,687,312 of Oct. 9, 1928 and particularly on page 6,lines 6 to 20 thereof.

As to the solvents to be added their subdivision into the groups A, B, Chas been made with regard to their function.

The solvent A performs the function of replacing the water in thecondensation products when still liquid, that is to say when they arestill in the state of the sol, whilst the solvent B serves for assuringthe capability of the concentrated product of being poured into themolds and this solvent must escape from the jelly during the hardening.Some of the solvents used possess both these functions.

The solvent C is destinated'to building up the final hardened gel andwithin the mass.

It is to be pointed out, that these different functions must notnecessarily be accomplished by different solvents. On the contraryin'practice operations are mostly carried out in such manner, that thesolvents A and B are identical. Only C is nearly always different from Aand B.

The action of these solvents is in no way a dehydrating one, as is forinstance the case with the action of the sulphuric acid, nor does achemical combination ofthese solvents with water take place, but theaction of the solvent is such, that it furnishes the amount of therespective liquid necessary for the formation of the sol and for thebuilding up of th jelly by replacing the water thereof.

therefore must remain the mixture is evaporated. Thereafter one part '8.A process for the production of condensa-' tion products from urea andformaldehyde, char- What I claim is:

i. In the process for manufacturing condensation products from a ureaand formaldehyde, the step which comprises adding to the initialcondensation products, prior to the sol being transformed into the gel,organic solvents possessing the property of forming with waterwaporsvolatile vapor mixtures and removing water from the reaction mixture bydistillation.

2. A process for the production of condensation products from urea andan aldehyde characterized by the fact that an organic fluid is added tothe watery solutions of the initial condensation product, such organicfluid being volatile with water vapor and driving off the water, in partat least, by the evaporation of the organic fluids, and at not laterthan the end of this evaporation step, adding an organic medium whichhas a higher boiling point than water and which like water, and in theplace of water participates in the formation of sols from thecondensation products, and gives clear solutions with them.

3. A process for the production of condensation products from urea andformaldehyde characterized by the fact that an organic fluid is added tothe watery solutions of the initial condensation product, such organicfluid being volatile with water vapor, and driving off the water, inpart, by the evaporation of the organic fluids, and that not later thanthe end of this evaporation step, an organic medium is added which has ahigher boiling point than water and which like water and in the place ofwater participates only in the formation of sols from the condensationproducts, and gives clear solutions with them.

4. A process for the production of condensation products from urea andformaldehyde characterized by the fact that an organic fluid is added tothe watery solutions of .the initial condensation product, such organicfluid being volatilewith water vapor, and driving ofi a part at least ofthe water by the evaporation of the organic fluids, and that not laterthan the end of this evaporation step, g lycerine is added.

5. A process for the production of condensation products from urea andformaldehyde char-- acterized by the fact that an organic fluid is addedto the watery solutions of the initial condensation product, suchorganic fluid being volatile with water vapor, driving off at least apart of thc'water by the evaporation of the organic fluids and that notlater than the end of this evaporation step, an alcoholic substancehaving a boiling point which is substantially above that of water isadded, such alcoholic substance being one that mixes clear with thecondensation product. e

6. The step of adding a plurality of organic solvents includingglycerine and liquids which form low boiling mixtures with water, to thesyrupy intermediate condensation product of urea and an aldehyde, andheating sufliciently to drive off at least a part of the water and-todrive oil at least a part of the other volatile solvents present,whereby a highly elastic resinous product is produced.

'7. In the formation of condensation products of urea and an aldehyde,the step of adding glycerine at a stagenot later than the finishing ofthe evaporation of liquid from the syrupy intermediate condensationproduct, substantially as described, the amount of such glycerine beingsufficient to aid in the condensation reaction and to form a transparentmass with such condensation product.

acterized by the fact that organic fluids are added to the waterysolutions of the initial condensation product, produced in any desiredmanner, which organic fluids are volatile with water vapor, that thewater and organic fluids are at least partly driven off by evaporationand that before the end of this evaporation, organic media are addedwhich have a higher boiling point than water and which participate onlyas sol-forming media in the formation of condensation products, and giveclearsolutions with them, and which are able to form clear gels with thecondensation properties.

9. Process for the production of organosols or organo-gels from a waterycondensation product of urea and formaldehyde, which comprises adding anorganic fluid to a water solution of the starting condensation product,the said fluid being volatile with water vapor, and evaporating suchfluid whereby the water present is at least partly driven off by meansof the organic fluid, and further organic media are added which giveclear solutions with the condensation products and which have a higherboiling point than water, so that they are not removed in the subsequentevaporation or hardening of the jelly, and which participate in theformation of the sol, similarly to water and in place of water, only assol forming means.

10. A composition comprising a hydrophobe urea-formaldehyde condensationproduct and an organic softening agent belonging to the group consistingof camphor, borneoi, acetanilide, anilide of benzoic acid, andnaphthalene.

11. A composition comprising a hydrophohe urea-formaldehyde condensationproduct and acetanilide.

12. In the process for manufacturing condensation products from a ureaand formaldehyde, the steps-which comprise adding an organic mediumpossessing the property of forming with water vapors volatile vapormixtures to an initial condensationproduct, and volatilizing water toform an organic solvent soluble reaction product.

13. In the process for manufacturing condensation products from aureaand formaldehyde, the steps which comprise reacting a urea and. aqueousformaldehyde to form an initial condensation product, and removing waterfrom said condensation product by heating in the presence of an alcoholuntil a product is obtained having substantially no water vapor tension.

14. In the process for manufacturing condensation products from a ureaand formaldehyde, in combination, the steps which comprise reactinga-urea and aqueous formaldehyde to form an initial condensation product,treating said condensation product with a non-aqueous medium, andvolatilizing water to form an organic solvent soluble reaction product.15. In the process for manufacturing condensation products of a urea andformaldehyde, in. combination, the steps which comprise removing waterfrom an initial condensation product by treating with a non-aqueousorganic medium capable of forming a volatile vapor mixture with watervapor and vaporizing said volatile mixture until an organicsolventsoluble reaction product is obtained. I

16. In the process for manufacturing condensation products of a urea andformaldehyde,

in combination, the steps which comprise eflecting reaction between aurea and formaldehyde in the presence, of a non-aqueous organic mediumcapable of forming a volatile vapor mixture with water vapors andvaporizing said volatile mixture to form an organic solvent solublereaction product.

17. A composition of matter comprising a hydrophobe urea formaldehydecondensation product having the characteristics of a product incombination, the steps which comprise react-. ing a urea and aqueousformaldehyde to form an initial condensation product, treating saidproduct with a non-aqueous volatile solvent, volatilizing water andsolvent mixture, adding a substantially non-volatile organic medium, andvolatilizing remaining volatile solvent and water to form an organicsolvent soluble product.

19. A composition comprising a hydrophobe urea condensation product anda non-volatile organic softening agent, said composition having thecharacteristics of a product produced by the process of claim 18.

